<PAGE>

                                 PROMISSORY NOTE

Dallas, Texas                    $11,500,000.00                     May 5, 1999

     CompUSA Inc., a Delaware corporation (the "Borrower"), for value 
received, promises to pay to the order of FIRST UNION NATIONAL BANK 
("Lender"), at the principal office of NationsBank, N.A., in lawful money of 
the United States of America, the principal sum ELEVEN MILLION FIVE HUNDRED 
THOUSAND AND NO/100 DOLLARS ($11,500,000.00), or such lesser sum as shall be 
due and payable from time to time hereunder, as hereinafter provided.  All 
terms used but not defined herein shall have the meanings set forth in the 
Credit Agreement described below.

     Principal of and interest on the unpaid principal balance of Advances 
under this Note from time to time outstanding shall be due and payable as set 
forth in the Credit Agreement.

     This Note is issued pursuant to and evidences Advances under a Second 
Amended and Restated Credit Agreement, dated as of March 14, 1998, among the 
Borrower, NationsBank, N.A. (successor by merger to NationsBank of Texas, 
N.A.), as Administrative Lender, certain Co-Agents and the lenders parties 
thereto (as amended, restated, supplemented, renewed, extended or otherwise 
modified from time to time, "Credit Agreement"), to which reference is made 
for a statement of the rights and obligations of the Lender and the duties 
and obligations of the Borrower in relation thereto; but neither this 
reference to the Credit Agreement nor any provision thereof shall affect or 
impair the absolute and unconditional obligation of the Borrower to pay the 
principal sum of and interest on this Note when due.  This Note is a 
replacement and modification (but not a novation of the debt evidenced 
thereby) of that certain Promissory Note, dated as of March 12, 1998, payable 
by the Borrower to the order of the Lender in the principal amount of 
$15,000,000.

     The Borrower and all endorsers, sureties and guarantors of this Note 
(without waiving any notice that any Lender is specifically required to give 
pursuant to SECTION 8.1 of the Credit Agreement) hereby severally waive 
demand, presentment for payment, protest, notice of protest, notice of 
intention to accelerate the maturity of this Note, notice of acceleration of 
this Note, diligence in collecting, the bringing of any suit against any 
party and any notice of or defense on account of any extensions, renewals, 
partial payments or changes in any manner of or in this Note or in any of its 
terms, provisions and covenants, or any releases or substitutions of any 
security, or any delay, indulgence or other act of any trustee or any holder 
hereof, whether before or after maturity.

<PAGE>

     THIS NOTE, TOGETHER WITH THE OTHER LOAN DOCUMENTS, REPRESENTS THE FINAL 
AGREEMENT BETWEEN THE PARTIES AND MAY NOT BE CONTRADICTED BY EVIDENCE OF 
PRIOR, CONTEMPORANEOUS, OR SUBSEQUENT ORAL AGREEMENTS OF THE PARTIES HERETO.  
THERE ARE NO UNWRITTEN ORAL AGREEMENTS BETWEEN THE PARTIES.

                                       CompUSA Inc.



                                       By:  s/James E. Skinner
                                          -------------------------------------
                                          James E. Skinner
                                          Executive Vice President


                                       -2-